Modification of tobacco powder by pyridine catalytic method obtained modified tobacco powder biomass adsorbent (MTPBA). This provides a technical basis for the comprehensive utilization of waste biomass resources and the management of NO₃^- contamination. Through the conditional experiments, taken MTPBA direct recover and NO₃^- adsorption rate of 2 mg/L as indicators, the influence of main parameter conditions in the preparation process of MTPBA was studied, and determined the suitable conditions for the preparation of MTPBA. The physicochemical characteristics of tobacco powder before and after modification were characterized by scanning electron microscopy, energy spectrum analyzer, Fourier transform infrared spectroscopy etc. The results show that the suitable conditions for preparing MTPBA are NaOH concentration of 1.5 mol/L during strong alkali pretreatment; the temperature of the crosslinking reaction is 80℃; the dosage of the crosslinking agent is 5 mL/g; the temperature of the quaternization reaction is 80℃. The formed MTPBA showed uniform morphology, increased crystallinity, formed a large number of fine pores on the surface, and successfully introduced tertiary amine groups and chloroalkyl groups. The results indicate that MTPBA has a better pore structure than the original tobacco powder, and the introduction of tertiary amine groups, chloroalkyl groups and surface zeta potential changes are favorable for adsorption of NO₃^-.